Atherectomy device

ABSTRACT

An atherectomy device for removing deposits such as plaque from an interior of a vessel including an outer member and a rotatable shaft positioned for rotational movement within the outer member. The outer member is fixed axially. A rotatable tip is mounted to the distal region of the rotatable shaft for rotation about its longitudinal axis upon rotation of the shaft. The rotatable shaft includes a guidewire lumen for receiving a guidewire to enable over the wire insertion of the device.

This application is a divisional of application Ser. No. 14/948,182,filed on Nov. 20, 2015, which claims priority from provisionalapplication 62/097,049, filed Dec. 27, 2014 and from provisionalapplication 62/199,999, filed Aug. 1, 2015. The entire contents of eachof these applications are incorporated herein by reference.

BACKGROUND Technical Field

This application relates to a vascular surgical apparatus, and moreparticularly to a minimally invasive device for removing plaque or otherdeposits from the interior of a vessel.

Background of Related Art

The vascular disease of atherosclerosis is the buildup of plaque orsubstances inside the vessel wall which reduces the size of thepassageway through the vessel, thereby restricting blood flow. Suchconstriction or narrowing of the passage in the vessel is referred to asstenosis. In the case of peripheral vascular disease, which isatherosclerosis of the vascular extremities, if the vessel constrictionis left untreated, the resulting insufficient blood flow can causeclaudication and possibly require amputation of the patient's limb. Inthe case of coronary artery disease, if left untreated, the blood flowthrough the coronary artery to the myocardium will become inadequatecausing myocardial infarction and possibly leading to stroke and evendeath.

There are currently several different treatments for treating arterialdisease. The most invasive treatment is major surgery. With peripheralvascular diseases, such as occlusion of the tibial artery, major surgeryinvolves implantation and attachment of a bypass graft to the artery sothe blood flow will bypass the occlusion. The surgery involves a largeincision, e.g., a 10 inch incision in the leg, is expensive and timeconsuming for the surgeon, increases patient pain and discomfort,results in a long patient recovery time, and has the increased risk ofinfection with the synthetic graft.

Major surgery for treating coronary artery disease is even more complex.In this surgery, commonly referred to as open heart surgery, a bypassgraft connects the heart to the vessel downstream of the occlusion,thereby bypassing the blockage. Bypass surgery requires opening thepatient's chest, is complex, has inherent risks to the patient, isexpensive and requires lengthy patient recovery time. Bypass surgeryalso requires use of a heart lung machine to pump the blood as the heartis stopped, which has its own risks and disadvantages. Oftentimes, thesaphenous vein in the patient's leg must be utilized as a bypass graft,requiring the additional invasive leg incision which further complicatesthe procedure, increases surgery time, lengthens the patient's recoverytime, can be painful to the patient, and increases the risk ofinfection.

Attempts to minimize the invasiveness of coronary bypass surgery arecurrently being utilized in certain instances. These typically includecreating a “window approach” to the heart. Although the window approachmay reduce patient trauma and recovery time relative to open heartsurgery, it still requires major surgery, and is a complicated anddifficult surgery to perform due to limited access and limitedinstrumentation for successfully performing the operation. Attempts toavoid the use of a heart lung machine by using heart stabilizationmethods has become more accepted, but again, this does not avoid majorsurgery.

Due to the invasiveness and potential for complications with majorperipheral or coronary vascular surgery, minimally invasive procedureshave been developed. Balloon angioplasty is one of the minimallyinvasive methods for treating vessel occlusion and obstructions. Acatheter having a balloon is inserted through the access artery, e.g.,the femoral artery in the patient's leg or the radial artery in the arm,and advanced through the vascular system to the occluded site over aguidewire. The deflated balloon is placed at the occlusion and inflatedto crack and stretch the plaque and other deposits to expand the openingin the vessel. Balloon angioplasty, especially in coronary surgery, isfrequently immediately followed by insertion of a stent, a smallmetallic expandable device which is placed inside the vessel wall toretain the opening which was created by the balloon. Balloon angioplastyhas several drawbacks including difficulty in forcing the balloonthrough the partially occluded passageway if there is hard occlusion,the risk involved in cutting off blood flow when the balloon is fullyinflated, the frequency of restenosis after a short period of time sincethe plaque is essentially stretched or cracked and not removed from thevessel wall or because of the development of intimal hyperplasia and thepossibility of balloon rupture when used in calcified lesions.

Another minimally invasive technique used to treat arteriosclerosis isreferred to as atherectomy and involves removal of the plaque by acutting or abrading instrument. This technique provides a minimallyinvasive alternative to the bypass surgery techniques described aboveand can provide an advantage over balloon angioplasty methods in certaininstances. Atherectomy procedures typically involve inserting a cuttingor ablating device through the access artery, e.g., the femoral arteryor the radial artery, and advancing it over a guidewire through thevascular system to the occluded region, and rotating the device at highspeed to cut through or ablate the plaque. The removed plaque ormaterial can then be suctioned out of the vessel or be of such finediameter that it is cleared by the reticuloendothelial system. Removalof the plaque in an atherectomy procedure has an advantage over balloonangioplasty plaque displacement since it debulks the material.

Examples of atherectomy devices in the prior art include U.S. Pat. Nos.4,990,134, 5,681,336, 5,938,670, and 6,015,420. These devices haveelliptical shaped tips which are rotated at high speeds to cut away theplaque and other deposits on the interior vessel wall. A well-knowndevice is marketed by Boston Scientific Corp. and referred to as theRotablator. As can be appreciated, in these devices, the region ofplaque removal is dictated by the outer diameter of the cutting tip(burr) since only portions of the plaque contacted by the rotating tipare removed. The greater the area of plaque removed, the larger thepassageway created through the vessel and the better the resulting bloodflow.

U.S. Pat. Nos. 5,217,474 and 6,096,054 disclose expandable cutting tips.These tips however are quite complex and require additional expansionand contraction steps by the surgeon.

U.S. Pat. No. 6,676,698 discloses an atherectomy device designed toobtain an optimal balance between the competing objectives of thesmallest introducer sheath size to facilitate insertion and reducetrauma to the vessel and the largest atherectomy tip size to remove alarger region of plaque or other deposits from the vessel wall.

However, it would be advantageous to enhance the breaking up and removalof the small particles in atherectomy procedures.

SUMMARY

The present invention provides in one aspect an atherectomy device forremoving deposits such as plaque from an interior of a vessel comprisinga housing, an outer member extending from the housing and having adistal end and a rotatable shaft positioned for rotational movementwithin the outer member, the shaft having a longitudinal axis, a distalregion and a distalmost edge. The outer member is fixed axially withrespect to the housing. A rotatable tip has a proximal end and a distalend. The proximal end of the rotatable tip is positioned distally of thedistal end of the outer member to create a gap between the proximal endof the rotatable tip and the distalmost edge of the outer member. Therotatable tip is mounted to the distal region of the rotatable shaft.The rotatable tip has a longitudinal axis and is mounted to therotatable shaft for rotation about its longitudinal axis upon rotationof the shaft. The shaft includes a guidewire lumen for receiving aguidewire to enable over the wire insertion of the device.

In some embodiments, the device includes an auger positioned on therotatable shaft, the auger positioned proximally of the rotatable tipand extending along the outer shaft, wherein rotation of the shaftrotates the auger to move particles abraded by the tip proximally intothe outer member.

In some embodiments, a portion of the auger is exposed between theproximal end of the rotatable tip and the distalmost edge of the outermember; in other embodiments, the auger is positioned within the outermember such that it is not exposed between the proximal end of therotatable tip and the distalmost edge of the outer member.

A coating can be provided over at least a portion of the rotatable shaftand/or auger.

A motor for rotating the rotatable shaft can be provided positionedwithin the housing.

In some embodiments, particles are aspirated through the outer member inthe space between the rotatable shaft and an inner wall of the outermember.

In some embodiments, the rotatable tip can be mounted proximal of thedistalmost end of the rotatable shaft.

The tip can have a lumen extending therethrough dimensioned to receivethe rotatable shaft.

In some embodiments, the rotatable tip is composed of first and secondcomponents, e.g., halves, the components radially spaced from eachother. In some embodiments, the first component is composed of amaterial having a density greater than the second component. In someembodiments, the first component has a portion removed so it is composedof less material than the second component.

In accordance with another aspect of the present disclosure a method forremoving deposits such as plaque from an interior of a vessel isprovided. The method comprises the steps of:

providing an introducer sheath having an internal diameter;

providing a deposit removal device including an outer member, arotatable shaft and a rotatable tip at a distal portion of the rotatableshaft, the outer member axially fixed (or substantially axially fixed)to maintain a fixed spacing between the distal end of the outer memberand proximal end of the rotatable tip;

inserting the introducer sheath through a skin incision and into avessel;

advancing the rotatable tip adjacent the deposits to be removed; and

actuating a motor to rotate the rotatable tip at high speed by rotationof the rotatable shaft to contact and remove the deposits, the rotatabletip rotating to remove deposits; and

aspirating deposits through a space in the outer member between theshaft and an inner wall of the outer member during rotation of therotatable shaft.

In some embodiments, the rotatable shaft can have an auger thereon sothe step of rotating the rotatable shaft causes the auger to directparticles proximally within the outer member.

The method in some embodiments further includes the step of applying avacuum to aspirate proximally deposits removed by rotational movement ofthe tip.

The method can further include the step of inserting the tip over aguidewire.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a perspective view of the distal portion of the atherectomydevice of one embodiment of the present invention;

FIG. 2 is a longitudinal cross-sectional view of the distal portion ofthe atherectomy device of FIG. 1;

FIG. 3 is a view similar to FIG. 2 showing aspiration through thecatheter;

FIG. 3A is a transverse cross-sectional view of the tip of FIG. 1;

FIG. 4 is a partial cross-sectional view of the distal portion of analternate embodiment of the atherectomy device of the present invention;

FIG. 5 is a cut away side view of the atherectomy bit of FIG. 4;

FIG. 6 is a transverse cross-sectional view taken along line 6-6 of FIG.5;

FIG. 7 is a cut away side view of the atherectomy bit of FIG. 4 showingthe opposite side of the side shown in FIG. 5;

FIG. 8 is a transverse cross-sectional view taken along line 8-8 of FIG.7;

FIG. 9 is a perspective view of a distal portion of another alternateembodiment of the atherectomy device of the present invention;

FIG. 10A is a transverse cross-sectional view of the bit of FIG. 4;

FIG. 10B is a view similar to FIG. 10A showing an alternate embodimentof the atherectomy bit of the present invention;

FIG. 11A is a perspective view of the distal portion of anotheralternate embodiment of the atherectomy device of the present invention;

FIG. 11B is a longitudinal cross-sectional view of the device of FIG.11A;

FIG. 12A is a perspective view of the distal portion of anotheralternate embodiment of the atherectomy device of the present invention;

FIG. 12B is a longitudinal cross-sectional view of the atherectomydevice of FIG. 12A;

FIG. 12C is a close up view of the area of detail identified in FIG.12B;

FIG. 13A is a perspective view of the distal portion of anotheralternate embodiment of the atherectomy device of the present invention;

FIG. 13B is a longitudinal cross-sectional view of the atherectomydevice of FIG. 13A;

FIG. 13C is a close up view of the area of detail identified in FIG.13B;

FIG. 14 is a side view of the housing of the atherectomy device of FIG.12A, with a housing half removed to show internal components;

FIG. 15 is an enlarged view of the area of detail identified in FIG. 14;

FIGS. 16A-16D show a method of use of the atherectomy device of FIG. 4wherein:

FIG. 16A is a side view in partial cross-section of the guidewire beinginserted through the vessel;

FIG. 16B is a side view in partial cross-section illustrating therotating shaft and bit of the atherectomy device inserted over theguidewire;

FIG. 16C is a view similar to FIG. 16B showing rotation of the shaft toremove plaque; and

FIG. 16D is a view similar to FIG. 16C showing further removal ofplaque;

FIG. 17 is a schematic view illustrating the atherectomy system of oneembodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to an atherectomy device designed forhigh speed rotation to remove plaque or other deposits on the insidewall of the vessel to widen the blood passageway therethrough. Toachieve such rotation, the atherectomy tip is positioned at a distalportion of a flexible rotatable shaft that can be gas or electricallypowered. The shaft rotates at high speed, typically between 100,000 and200,000 rpm, causing the cutting or ablation surface of the tip toremove the plaque and deposits to which it comes into contact. Theatherectomy device of the present invention has application in a varietyof vessels such as the coronary arteries, peripheral vessels such as thetibial artery, femoral, and popliteal, and saphenous vein bypass grafts.

In order for the atherectomy tip to reach the vessel stenosis(obstruction) it is supported on a flexible shaft and inserted alongwith the flexible shaft through an introducer sheath and over aguidewire. More specifically, the introducer sheath is placed through askin incision and into a vessel, e.g., the femoral artery in thepatient's leg, to provide access to the target site. A guidewire is theninserted through the introducer sheath and advanced through theappropriate vessels to the target obstructed site, typically thecoronary artery. The flexible shaft and attached atherectomy tip,extending from a catheter, are then inserted through the introducersheath and threaded over the length of the guidewire to the targetobstructed site. Actuation of the motor spins the shaft and tip so thecutting surface repeatedly comes into contact with the obstruction,e.g., plaque, to remove it from the vessel wall.

Details of the present invention will now be described with reference tothe drawings wherein like reference numerals identify similar or likecomponents throughout the several views.

FIG. 1 illustrates one embodiment of the atherectomy device of thepresent invention, designated generally by reference numeral 10. Theentire device is shown in FIG. 17; the distal portion of the device isshown in FIGS. 1-3. The atherectomy tip or bit 12 of the device 10 isconnected to a flexible rotatable inner shaft 20 such that rotation ofthe inner shaft 20 rotates the tip 12. The inner shaft 20 is positionedin outer tube or catheter 24. As shown, the tip 12 is connected at adistal region of the rotatable shaft 20, but preferably spaced from adistalmost end 22 of the shaft 20. In an alternate embodiment, it isplaced at the distalmost end of the flexible shaft 20. The flexibleshaft 20 is electrically powered for high speed rotation to rotate theshaft 20 and tip 12 to break up plaque to treat stenosis of a vessel. Amotor housing 2, shown schematically in FIG. 17, contains a motormounted therein and a motor shaft. The atherectomy device 10 isoperatively connected to the motor housing 2 as the flexible shaft 20 isconnected to the motor such that activation of the motor rotates theshaft 20 of the device. A control knob can be provided to adjust therotational speed of the shaft 20 and tip 12, and a window can beprovided to visually display the speed. Shaft 20 and tip 12 can bedisposable. In use, an introducer sheath or catheter 35 is insertedthrough an incision “A” in the patient's leg and through an incision inthe femoral artery “B”. The catheter or outer tube 24 with attachedshaft 20 (positioned therein) and tip 30 are introduced through theintroducer sheath into the femoral artery “B”, and advanced to thetarget artery, e.g., the coronary artery, to the treatment obstructionsite. Note that a guidewire G extends through the shaft 20 and into thetarget artery so that the shaft 20 and tip 12 are inserted over theguidewire. FIG. 17 illustrates an exemplary introducer sheath 35.

The system in some embodiments further includes an aspiration (vacuum)source 5, shown schematically in FIG. 17, communicating with thecatheter 24 to aspirate particles through the catheter 24 in the space(lumen 27) between the inner wall 24 a of the catheter 24 and outer wallof shaft 20 (FIG. 2). Tubing 7 extends from the aspiration source 5 tocommunicate with the catheter 24 via catheter hub 28, and in someembodiments through a side arm (not shown) in catheter hub 28. Thesystem in some embodiments can have an aspiration (vacuum) source 4communicating via tubing 8 with the introducer sheath 35 via hub 29, andin some embodiments through a side port (not shown) in hub 29, toprovide aspiration in the space between the inner wall of sheath 35 andthe outer wall of catheter 24. Note the aspiration through theintroducer sheath 35, if provided, can be in addition to the aspirationthrough catheter 24 or alternatively the sole source of aspiration inwhich instance aspiration source 5 would not be provided. The system canalso include a fluid source 6 for delivering fluids to the vessel.Tubing 11 extends from the fluid source 6, through catheter hub 28, andin some embodiments through a side arm (not shown) in catheter hub 28,to communicate with the inner lumen 27 of catheter 24 or through thelumen of the shaft 20 so fluid can be introduced to the vessel.

It should be appreciated that the device 10 is shown inserted throughthe femoral artery by way of example as other vessels can be utilizedfor access, such as the radial artery. Also, the tip of the presentinvention can be used to remove plaque or other obstructions in avariety of vessels such as the coronary artery, the tibial artery, thesuperficial femoral, popliteal, saphenous vein bypass grafts and instentrestenosis.

With reference to FIGS. 1-3, the first embodiment of the rotatableatherectomy tip of the present invention will now be described in moredetail. Tip or burr 12 has a front (distal) portion (section) 14, a rear(proximal) portion (section) 16, and an intermediate portion (section)18 between the front and rear portions 14 and 16. These portions vary intransverse cross-section as can be appreciated by the Figures. Thus, thefront portion 14 can be defined for convenience as the area starting atthe distalmost tip 17, forming a bullet nose configuration. Thecross-section of the front portion 14 in one embodiment is substantiallycircular in configuration. The intermediate portion 18 can be consideredas the region where the tip 12 transitions into the scalloped region 19.The cross-section of the intermediate portion 18 progressively changesfrom substantially circular, to an elongated shape having twosubstantially flat or linear opposing sidewalls 16 a. This can also beviewed as removed material from the otherwise conical shape so that thedistance between opposing linear walls 16 a is less than the distancebetween opposing walls 19 a.

Rear portion 16 can be considered to begin, for convenience, in thescalloped region 19, and terminate at the proximalmost edge 13 of tip12. The rear portion 16 preferably has the same elongatedcross-sectional dimension throughout its length, with substantiallylinear walls 16 a separated by a distance less than the distance betweenopposing walls 19 a.

The scalloped or narrowed section 19 is formed in both sides of the tip12 to reduce the profile of the tip 12. These scalloped sections formthe aforedescribed opposing substantially linear walls. By reducing theprofile, i.e., the diameter and circumference, the atherectomy tip ofthe present invention could be inserted through smaller introducersheaths than would otherwise be the case if the circumference increasedwith increasing diameter.

It should also be appreciated that the front, intermediate and rearportions/sections are designated for convenience and are not intended torequire three separate segments connected together. Tip 12 can be, andis preferably, a monolithic piece.

Tip 12 has a proximal or rear opening 32 and a distal or front opening34 connected by a lumen. The flexible shaft 20 extends through openings32, 34 and the lumen and is attached to the tip 12. In some embodiments,the tip 12 is attached such that the shaft 20 extends through frontopening 34 and extends a short distance distal of distalmost edge 17 oftip 12 as shown in FIG. 2. Shaft 20 has a lumen 25 dimensioned toreceive a guidewire G to enable over the wire insertion of theatherectomy device 10.

The region of plaque removal is defined by the largest diameter regionof the tip since the tip is rotating at high speeds and the plaque iscut or abraded only where the tip comes into contact with it. However,the sheath size required is determined by the largest circumferenceregion of the tip. In some embodiments, the region of plaque removal canbe further increased by altering the geometry and/or material of the tip12 to create a wobbling effect which is described in more detail below.

As a result of the scalloped sections of the tip 12, as the diameter oftip 12 increases in one orientation, it decreases in the transverseorientation, enabling the circumference to remain constant. Since thediameter is reduced in one transverse orientation, the tip 12 can beintroduced into an introducer sheath having an internal diameterslightly less than the largest diameter of the tip, since the sheath hasroom to deform because of the reduced regions, i.e., the scallopedsections, of the tip 12. In the prior art elliptical tip, the roundedsymmetrical configuration leaves no room for the sheath to deform so thesheath size must exceed the largest diameter region. Thus, the tip 12can fit into conventional introducer sheaths having an internal diameterless than the largest outer diameter of the tip 12. This can be achievedby the fact that the tip 12 can deform the internal walls of the sheathas it is inserted, by ovalizing the sheath. If the scalloped walls werenot provided, the sheath would need to stretch, rather than ovalize toallow an oversized tip to pass.

Another way to view the tip 12 is that for a given catheter French sizedesired to be used by the surgeon, a larger atherectomy tip can beutilized if the atherectomy tip 12 of the present invention is selectedinstead of the prior art elliptical tip, thereby advantageouslyincreasing the region of plaque removal to create a larger passageway inthe vessel.

In alternate embodiments of the tip 12, longitudinal or elongatedcircular and oval cutting grooves could be provided to provide aroughened surface to cut or ablate the plaque as the tip is rotated. Thegrooves or indentations can be formed by laser cutting a series ofgrooves extending longitudinally within the interior of the tip stock.The tip is then ground to remove portions of the outer surface topartially communicate with the grooves, thereby creating indentationsforming a roughened surface for contact with the plaque. The resultingformation is a series of elongated cutouts/indentations on the front andintermediate portions and oval shaped cutouts/indentations on the distaland intermediate portions. Another way contemplated to create theroughened surface is by blasting, e.g. sandblasting or grit blasting,the tip. The tip is held in a fixture and blasted at a certain pressure,thereby removing portions of the outer surface to create a roughenedsurface. Creation of a roughened surface by chemical etching is alsocontemplated. In an alternate embodiment, an abrasive coating, such asdiamond particles, is applied to the tip. It should be appreciated thatthe foregoing roughened surfaces, abrasive coating, etc. can be appliedto any of the atherectomy tips described herein.

FIG. 9 illustrates an alternate embodiment of the atherectomy tip. Inthis embodiment, the tip, designated generally by reference numeral 50,does not have scalloped sections but instead is substantiallycylindrical in configuration along its length except for the bullet nosetip 52. That is, it is circular in transverse cross-section throughoutits length. In all other respects, the atherectomy device of FIG. 9 isthe same as FIG. 1, i.e., includes rotatable shaft 20 extending beyondthe atherectomy tip, catheter 24, etc., so for brevity these componentswill not be discussed herein since the discussion of these componentswith respect to FIG. 1 are fully applicable to the embodiment of FIG. 9.

In some embodiments, the atherectomy tip is symmetrical. In alternateembodiments, the outer geometry of the tip is symmetrical, however, aninner portion of one side of the tip is carved out or removed to createan imbalance resulting in an offset center of mass. This results inwobbling of the tip during high speed rotation which in turn enables aspinning diameter to exceed the cross-sectional dimension of the tip. Inthis manner, the tip can be used to remove plaque in a wider transversearea. This is shown in FIG. 3A with material removed from one side ofthe tip 12 to create a cutout or removed material section 15.

Removing material from one side of the tip is one way to achieve thiswobbling effect. Another way is through the tip itself being composed ofmaterials of different density, either the same material of differentdensities or different materials of a differing density such as in FIG.10B. Such materials utilized can include by way of example platinum andaluminum. These two ways of achieving the wobbling effect are alsodiscussed below in conjunction with the two piece tip.

Referring back to FIGS. 1-3, as shown, the tip 12 is fixed to therotatable shaft 20 and positioned distal of the distalmost end of thecatheter 24. The shaft 20 is axially fixed within catheter (outer memberor outer tube) 24 but can rotate with respect to the catheter 24. Suchfixation is described below in conjunction with the embodiment of FIG.12A. The tip 12 therefore remains distal of the distal opening 23 in thecatheter 24 to maintain the gap e.g., a fixed gap between the proximaledge 13 of the tip 12 and the opening 23 so particles can be aspiratedthrough the opening 23 and lumen 27 of the catheter 24.

In the alternate embodiment of FIGS. 11A and 11B, device 40 includes arotatable shaft 42 having an auger or series of threads 44 proximal oftip or bit 45. The auger 44 is positioned on the region of the shaft 42proximal of the proximal edge 49 of tip 45 and extends along a length ofthe shaft 42 within catheter (outer tube) 47. These threads 44 functionas an Archimedes screw, i.e., a screw pump, to remove the plaque. Thatis, as the shaft 42 is rotated in the same manner as shaft 20, thescrew's helical surface scoops particles and directs the particlesproximally (rearwardly) along the shaft 42 through the lumen of catheter47. In all other respects, device 40 is identical to device 10. Theauger 44 can be used in addition to an aspiration pump for aspiratingparticles into the opening 48 of catheter 47 (as in the embodiment ofFIGS. 1-3) or alternatively used as a substitute so it provides the solemechanism for aspirating particles through the lumen of the catheter 47.The auger 44 can extend along the entire length or along a partiallength of the shaft 20. The auger 44 for removing particles can be usedwith any of the atherectomy devices disclosed herein.

FIGS. 4-8, 10A and 10B illustrate alternate embodiments of theatherectomy tip of the present invention wherein the tip is composed oftwo separated components. More particularly, in the embodiment of FIGS.4-8 and 10A, the tip 60 of atherectomy device 61 has a first component62 and a second component 64. Tip 60 is mounted on rotatable shaft 70(similar to shaft 20) at a position spaced proximally from thedistalmost edge 72 of the shaft 70 so that a distal portion of the shaft70 extends slightly distally of the distalmost edge 65 of tip 60. Shaft70 is rotatably mounted within lumen 82 of catheter 80 but axially fixedwithin catheter 80 to create a fixed gap between the tip 60 and catheter80. The shaft 70 has a lumen for insertion over a guidewire G.

With reference to FIGS. 5-8 and 10A, tip component 62 has a cutout orremoved material portion 66 to reduce the amount of material of the tip.Tip component 64 does not have such cutout. In this manner, due to thematerial imbalance which creates an offset center of mass, the tip 60will wobble when rotated to remove plaque in an area greater than atransverse dimension of the tip 60.

In the embodiment of FIG. 10B, the two tip components 62′, 64′ havedifferent densities to achieve the wobbling effect. The tip components62′, 64′ are attached to rotatable shaft 70′ which is fixed to catheter(outer member) 80′. Shaft 70′ and catheter 80′ are identical to theaforedescribed shafts 20 and 70 and catheters (outer member) 24 and 80.

FIGS. 12A-12C illustrate an alternate embodiment of the atherectomydevice. The device 90 includes a rotatable atherectomy tip or bit 92similar in configuration to tip 50 of FIG. 9. Rotatable tip 92 has alumen between its proximal and distal openings through which flexiblerotatable shaft 94 partially extends, terminating proximal of the distalopening of tip 92. That is, tip 92 is attached to rotatable shaft 94 ata distal end so the shaft 92 does not extend beyond the distalmost end93 of tip 92. Stated another away, a distal portion of the tip 92extends distally of the distalmost end 97 of shaft 94. Alternatively,the tip 92 can be attached to the flexible shaft spaced proximally ofthe distalmost end of the shaft 94 so a portion of the shaft 94 extendsdistally of the distalmost tip 93 of tip 92 in the same manner as in theembodiments of FIGS. 1 and 9. Shaft 94, like shaft 20, has a lumendimensioned to receive a guidewire G to enable over the wire insertionof the atherectomy device 90.

Rotatable shaft 94 has an auger or series of threads 96 proximal of tipor bit 92. The auger 96 is attached to the shaft 94, e.g., by welding atseveral regions, and is positioned on the region of the shaft 94proximal of the proximalmost edge 95 of tip 92 and extends along alength of the shaft 94 within outer tube or catheter 100. These threadsfunction as an Archimedes screw, i.e., a screw pump, to remove theplaque in the same manner as auger 44 described above. That is, as theshaft 94 is rotated, the screw's helical surface scoops particles anddirects the particles proximally (rearwardly) through opening 104 andalong the shaft 94 through the lumen 102 of catheter 100. The auger 96can be used in addition to an aspiration pump for aspirating particlesinto the distal opening of catheter 100 (as in the embodiment of FIGS.1-3) or alternatively used as a substitute so it provides the solemechanism for aspirating particles through the lumen 102 of the catheter100. The auger 94 has a portion exposed between the distal end 103 ofcatheter 100 and the proximal end 95 of shaft 94 as shown.

A coating 98 can be provided over the rotatable shaft 92, including overthe auger 96. The coating covers at least the distal portion of therotatable shaft 92, i.e., the portion exposed from the catheter 100.That is, the coating 98 can start just proximally of the tip 92 andextend to cover only the portion of the shaft 92 between the proximalend 95 of tip 92 and the distal end 103 of catheter 100. Alternatively,the coating 98 can cover other regions of the shaft 94, and in someembodiments, can cover the entire length of the shaft 92 including theregion of the shaft 94 within tip 92 as shown in FIG. 12B. Examples ofcoatings that can be utilized include PTFE or PET, although othermaterials are also contemplated. The coating covers the coils of therotatable shaft 92 so they do not pinch the vessel. The coating canfurther function to help hold the auger 96 close to the rotatable shaft94. It should be appreciated that the coating can be utilized with theother embodiments described herein.

In the embodiment of FIGS. 12A-12C, the auger 96 is exposed between thedistal end 103 of catheter 100 and the proximal end of the tip (bit) 92.In the alternate embodiment of FIGS. 13A-13C, the auger 116 ofatherectomy device 100 is not exposed between the distal end 124 ordistalmost edge of catheter 120 and the proximal end 115 or edge of thetip 112. That is, the auger 116 terminates at a distal end within thecatheter 120. In all other respects, device 120 is identical to device90 of FIGS. 12A-12C.

A coating 118 can be provided over the rotatable shaft 114, includingover the auger 116 in the same manner as shaft 94 described above. Thecoating 118, as in coating 98, covers at least the distal portion of therotatable shaft 114, i.e., the portion exposed from the catheter120—starting just proximally of the tip 112 and extending to cover onlythe portion between the tip 112 and the distal end 124 of catheter 120.Alternatively, the coating 118 can cover other regions of the shaft 114,and in some embodiments, can cover the entire length of the shaft 114.

As discussed above, the catheters of the various embodiments disclosedherein are axially (and rotatably) fixed with respect to the motor andmotor housing. The shafts are rotatably mounted to the motor but axiallyfixed with respect to the motor, (and motor housing). In this manner,actuation of the motor rotates the shaft and attached atherectomy tipwhile the position of the tip with respect to the catheter remains fixedsince the catheter (and rotatable shaft) are axially fixed, i.e., do notmove in an axial direction. In this manner, a gap, e.g., a fixed gap,between the atherectomy tip and the catheter is maintained to enableaspiration of particles into the distal end of the catheter, either bythe rotating auger or a vacuum, or the combination of both the auger andvacuum, as described herein.

FIGS. 14 and 15 illustrate an exemplary mounting of the rotatable shaftto the motor. The mounting is shown for the atherectomy device 90 ofFIG. 12A, it being understood that the atherectomy devices of the otherembodiments described herein can be mounted in the same fashion. Asshown, handle or motor housing 130 has an internal rib 136 affixedbetween rings 137 of hub 134 of atherectomy device 90. Catheter 100 isfixedly mounted to the hub 134 and extends distally thereof. A proximalrib 140 within housing 130 receives a more proximal portion of hub 134and provides additional support. Thus, hub 134 and attached catheter 100are fixedly mounted within the motor housing 130. The rotatable shaft94, extending through hub 134, is unattached to catheter 100 androtatably operatively connected to motor shaft 138. The shaft 94 isaxially fixed.

A series of wires 139 extend from the motor and terminate in a plug forpowering the motor. Aspiration tube 132 extends from side port 135 ofhub 134 to remove aspirated particles.

Use of the atherectomy tip of the present invention is illustrated inFIGS. 16A-16D. The tip 60 of FIG. 4 is shown in these drawings, it beingunderstood that the other atherectomy devices and tips disclosed hereinwould be used in the same insertion and rotational manner. As shown inFIG. 16A, plaque “P” buildup on the interior wall of the vessel “V” hasoccluded the passageway through the vessel. Rotational shaft 70 withattached tip 60 (or any of the other tips disclosed herein) is insertedover guidewire G and by motorized rotation of flexible rotatable shaft70 is rotated at high speed in the direction of the arrow in FIG. 16B toremove plaque which comes into contact with its outer surface.Aspiration is provided to aspirate the broken off particles throughopening 74 in catheter 72. The fixed gap between the distal edge 75 ofcatheter 72 and the proximalmost edge 63 of tip 62 provides space forthe particles to be suctioned through opening 74 and remains constantsince the catheter 72 and shaft 70 do not move axially. Thus, the cutplaque and debris can be removed from the patient's body as theparticles are dislodged by the rotating tip 60 as shown in FIG. 16C. Asthe plaque is removed, the device is continually advanced to continue toremove and aspirate the plaque as shown in FIG. 16D. As noted above, anauger like auger 44 or 96 can be provided in lieu of or in addition toan aspiration source

Note the term axially fixed as used herein means the component does notmove axially. However, axially fixed can also be considered to includesubstantially axially fixed such that significant axial movement isprevented so that the distance between the catheter and tip does notsignificantly change to affect aspiration. Similarly, a fixed gap canmean a substantially fixed gap so that the distance between the catheterand tip does not significantly change.

It should be appreciated that any of the tips described herein can beutilized with any of the rotatable shafts/catheters (outer members)disclosed herein.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

What is claimed is:
 1. A method for removing deposits such as plaquefrom an interior of a vessel comprising the steps of: providing anintroducer sheath having an internal diameter; providing a depositremoval device including an outer member, a rotatable shaft and arotatable tip at a distal portion of the rotatable shaft, the outermember axially fixed to maintain a fixed spacing between a distal end ofthe outer member and a proximal end of the rotatable tip, and therotatable tip having a fixed length defined between a proximalmost endand a distalmost end; inserting the introducer sheath through a skinincision and into a vessel; advancing the rotatable tip adjacent thedeposits to be removed, the rotatable tip maintaining the fixed lengthduring advancement; actuating a motor to rotate the rotatable tip athigh speed by rotation of the rotatable shaft to contact and remove thedeposits, the rotatable tip rotating to remove deposits, the rotatabletip maintaining the fixed length during rotation such that thedistalmost end and proximalmost end of the rotatable tip maintain afixed distance during advancing and rotating the rotatable tip; andaspirating deposits through a space in the outer member between therotatable shaft and an inner wall of the outer member during rotation ofthe rotatable shaft, the rotatable tip maintaining the fixed lengthduring aspiration.
 2. The method of claim 1, wherein the rotatable shafthas an auger thereon, and the step of rotating the rotatable shaftcauses the auger to direct deposits proximally within the outer member.3. The method of claim 2, wherein the step of aspirating depositsincludes applying a vacuum to aspirate direct deposits proximally thatare removed by rotational movement of the rotatable tip.
 4. The methodof claim 2, further comprising the step of inserting the rotatable tipover a guidewire.
 5. The method of claim 4, wherein during insertion anduse the distalmost end of the rotatable tip is a fixed distance from amotor and motor housing.
 6. The method of claim 4, wherein across-sectional dimension of the rotatable tip remains the same duringadvancing, rotation and aspiration.
 7. The method of claim 1, whereinthe step of aspirating deposits includes applying a vacuum to aspiratedirect deposits proximally that are removed by rotational movement ofthe rotatable tip.
 8. The method of claim 1, wherein the outer member isaxially fixed to a motor housing.
 9. The method of claim 8, furthercomprising aspirating deposits in a space between an inner wall of theintroducer sheath and an outer wall of the outer member.
 10. The methodof claim 1, further comprising aspirating deposits in a space between aninner wall of the introducer sheath and an outer wall of the outermember.
 11. The method of claim 1, wherein the rotatable tip as iscomposed of first and second components of different densities.
 12. Themethod of claim 1, wherein the rotatable tip extends distally of adistalmost end of the rotatable shaft.
 13. The method of claim 1,wherein the rotatable tip is spaced proximally of a distalmost end ofthe rotatable shaft.
 14. The method of claim 1, wherein the rotatableshaft has a coating thereover so coils of the rotatable shaft do notpinch the vessel.
 15. The method of claim 1, wherein during insertionand use the distalmost end of the rotatable tip is a fixed distance froma motor and motor housing.
 16. The method of claim 1, wherein across-sectional dimension of the rotatable tip remains the same duringadvancing, rotation and aspiration.